Combustion engines include a plurality of cylinders. Ignition timing and fuel injection may be controlled equally or differently for each cylinder. But variations in manufacturing and use result in combustion variability between cylinders. Ignition timing may be varied to balance torque produced by the cylinders. The air/fuel ratio may also be controlled by controlling the fuel injectors.
Combustion engines may regenerate exhaust gas for efficiency or environmental reasons. Some cylinders may be dedicated to exhaust gas recirculation (EGR) while the exhaust gas from other cylinders, the non-dedicated cylinders, is not recirculated. The air/fuel ratio and EGR ratio may be controlled to achieve desirable combustion.
In view of the complexity of combustion engines with EGR, it would be desirable to provide additional control mechanisms to further improve the operation of combustion engines.